| 1. |
- Bezerra-Neto, Manoel M., et al.
(författare)
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Complex magnetic structure of clusters and chains of Ni and Fe on Pt(111)
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 3054-
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Tidskriftsartikel (refereegranskat)abstract
- We present an approach to control the magnetic structure of adatoms adsorbed on a substrate having a high magnetic susceptibility. Using finite Ni-Pt and Fe-Pt nanowires and nanostructures on Pt(111) surfaces, our ab initio results show that it is possible to tune the exchange interaction and magnetic configuration of magnetic adatoms (Fe or Ni) by introducing different numbers of Pt atoms to link them, or by including edge effects. The exchange interaction between Ni (or Fe) adatoms on Pt(111) can be considerably increased by introducing Pt chains to link them. The magnetic ordering can be regulated allowing for ferromagnetic or antiferromagnetic configurations. Noncollinear magnetic alignments can also be stabilized by changing the number of Pt-mediated atoms. An Fe-Pt triangularly-shaped nanostructure adsorbed on Pt(111) shows the most complex magnetic structure of the systems considered here: a spin-spiral type of magnetic order that changes its propagation direction at the triangle vertices.
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| 2. |
- Bergman, Anders, et al.
(författare)
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A first-principles study of the magnetism and electronic structure of Cr clusters supported on a Au(111) surface
- 2007
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 19:15, s. 156226-
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Tidskriftsartikel (refereegranskat)abstract
- We have studied clusters of Cr on a Au(111) surface by means of a first-principles method that allows for non-collinear magnetic ordering. We find that the Cr atoms possess a large magnetic moment, of order 4 μB/atom, and have essentially antiferromagnetic interatomic exchange interactions. This leads to collinear magnetic arrangements in linear clusters (dimers and trimers) and non-collinear ordering in clusters where antiferromagnetism becomes frustrated, such as in triangular geometries.
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| 3. |
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| 4. |
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| 5. |
- Bergman, Anders, et al.
(författare)
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Non-collinear magnetisation of V clusters supported on a Cu (111) surface : Theory
- 2006
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 600:21, s. 4838-4842
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic properties and electronic structure of V clusters supported on a Cu (111) substrate, have been calculated from a first principles method. We observe in general non-collinear magnetic structures that are the result of antiferromagnetic interactions on a frustrated lattice. The values of the magnetic moments range from similar to 0 to 2.7 mu(B)/atom, depending on cluster geometry.
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| 6. |
- Cardias, Ramon, et al.
(författare)
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Unraveling the connection between high-order magnetic interactions and local-to-global spin Hamiltonian in noncollinear magnetic dimers
- 2023
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Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 108:22
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Tidskriftsartikel (refereegranskat)abstract
- A spin Hamiltonian that characterizes interatomic interactions between spin moments is highly valuable in predicting and comprehending the magnetic properties of materials. Here, we explore a method for explicitly calculating interatomic exchange interactions in noncollinear configurations of magnetic materials considering only a bilinear spin Hamiltonian in a local scenario. Based on density-functional theory calculations of dimers adsorbed on metallic surfaces, and with a focus on the Dzyaloshinskii-Moriya interaction (DMI) which is essential for stabilizing chiral noncollinear magnetic states, we discuss the interpretation of the DMI when decomposed into microscopic electron and spin densities and currents. We clarify the distinct origins of spin currents induced in the system and their connection to the DMI. In addition, we reveal how noncollinearity affects the usual DMI, which is solely induced by spin-orbit coupling, and DMI-like interactions brought about by noncollinearity. We explain how the dependence of the DMI on the magnetic configuration establishes a connection between high-order magnetic interactions, enabling the transition from a local to a global spin Hamiltonian.
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| 7. |
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| 8. |
- Carvalho, Pamela C., et al.
(författare)
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Correlation of Interface Interdiffusion and Skyrmionic Phases
- 2023
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 23:11, s. 4854-4861
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic skyrmions are prime candidates for the nextgenerationof spintronic devices. Skyrmions and other topological magnetic structuresare known to be stabilized by the Dzyaloshinskii-Moriya interaction(DMI) that occurs when the inversion symmetry is broken in thin films.Here, we show by first-principles calculations and atomistic spindynamics simulations that metastable skyrmionic states can also befound in nominally symmetric multilayered systems. We demonstratethat this is correlated with the large enhancement of the DMI strengthdue to the presence of local defects. In particular, we find thatmetastable skyrmions can occur in Pd/Co/Pd multilayers without externalmagnetic fields and can be stable even near room temperature conditions.Our theoretical findings corroborate with magnetic force microscopyimages and X-ray magnetic circular dichroism measurements and highlightthe possibility of tuning the intensity of DMI by using interdiffusionat thin film interfaces.
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| 9. |
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| 10. |
- Robles, Roberto, et al.
(författare)
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Spin and orbital moments of Fe clusters supported on Ni(001)
- 2008
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 20:1, s. 015001-
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Tidskriftsartikel (refereegranskat)abstract
- The spin and orbital moments for small Fe clusters deposited on a Ni(001) surface have been calculated by means of an ab initio method. We find enhanced spin and orbital moments compared to what is found in bulk Fe. Our obtained spin moments are in good agreement with previous theoretical studies on similar systems. Comparing our results with a recent x-ray magnetic circular dichroism study (Lau et al 2002 Phys. Rev. Lett. 89 057201), we find that the calculated orbital moments are much lower than those experimentally found. Reasons for this discrepancy are discussed.
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